Grinding machines

ABSTRACT

In a grinding machine comprising a motor-driven grinding wheel and a headstock for holding a workpiece to be ground by the grinding wheel, the base for supporting the grinding wheel is secured to a stationary bed, a table for supporting the headstock is slidably mounted on the bed and a feed shaft is provided for the table to feed it toward the grinding wheel. The feed shaft is located in a plane perpendicular to the axis of the grinding wheel and passing through substantially the center of the width of the grinding wheel.

Asann ell all,

[151 gnawin lleh. 22 1972 [54] GRKNDHNG MAtCHHNEfi 2,814,169 11/1957Martin ..51/l05 1R 3,344,559 10/1967 Inaba et al ..5l/105 R [72]Inventors: ll-liroaki Asnno; Tsuynslhi Koide; Dino Ohth gw li'llimhlKobaywhl, all Primary Examiner0thell M. Simpson 0f li r y h JapanAttorney-Wenderoth, Lind & Ponack [73 Assignec: Toyoda Mold imnnsiiiinimam, Kariyashi, Aichi-ken, Japan [22] Filed: Aug. 21, 11970 21 A 1 N 6594-2 [57] Ms cT 1 In a grinding machine comprising a motor-drivengrinding wheel and a headstock for holding a workpiece to be ground [30]Foreign Application Priority Data by the grinding wheel, the base forsupporting the grinding wheel is secured to a stationary bed, a tablefor supporting the Aug. 30, 1969 Japan ..44/68866 headstock is slidablymounted on the bed and a feed Shaft is provided for the table to feed ittoward the grinding wheel. U.S. The feed Shaft is located in a planeperpendicular to the axis of [51] "1324b B24) 17/00 the grinding wheeland passing through substantially the [58] Field M Search ..51/95, 95.1,105 center of the width of the grinding h [56] References {Zited 7Claims, ill Drawing Figures UNITED STATES PATENTS .u"1'ZZ"S317?,LLJIJ'IUQQLZ w 1 2 28 M 1H 15 ll 20 1 l l v r I oPATENYEnFEB22 I972 3,643,383

sum 1 [1F 6 HIROAKI ASANO, TSUYOSHI KOIDE, IKUO OHTSU,

SHOZO HAYASHI and IIIROSHI KOBAYASHI,

INVENTORS BY JMM ATTORNEYS PAIENlEurwzz 1912 133M383 SHEET 2 0F 6 \D LLHIROAKI ASANO,

ISUYOSHI KOIDE,

IKUO OHTSU, SHOZO HAYASHI and HIROSHI KOBAYASHI,

I NVENTOR ATTORNEYS BY 60% [WW saw 4 OF .6

PAIENIEDFEB 2 2 I972 HIROAKI ASANO TSUYOSHI KOIDE, IKUO OHTSU SHO HAYA SHI and HIR HI :KOBAYASHI,

INVENTORS m/Mam ATTORNEY;

HIROAKI ASANO, TSUYOSHI KOIDE IKUO OHTSU,

SHOZO HAYASHI and HIROS HI KOBAYASHI I N VENTORS uhwlwd. flu

ATTORNEYS PMENIEDFEB 2 2 I972 SHEET 5 [1F 6 PMENIEDFEB 22 m2 TSUYOSHIKOIDE,

IKUO OHTSU,

SHOZO HAYASHI & HIROSHI KJBAYASHI,

INVENTOR S M)! Mia! .IM

ATTORNEYS BACKGROUND OF THE INVENTION This invention relates to agrinding machine, more particularly to grinding machines operating athigh speeds.

To improve the grinding efiiciency of a grinding machine, the peripheralspeed of the grinding wheel and the grinding speed thereof have beengreatly increased in modern grinding machines. However, such high-speedgrinding operations require driving motors of increased power, weightand dimensions. To reduce vibration of the large-size motor it isnecessary to use a massive supporting base. In the prior grindingmachine, the driving motor is fixed to the supporting base and thegrinding wheelbase is fed by the motor to perform the grinding operationso that large weight or vibration of the driving motor affect the finefeeding of the grinding wheelbase or its accurate stopping thusdecreasing the accuracy of the grinding operation. Further, in such afeed mechanism of the grinding wheelbase, since the grinding wheel issupported by its base in a cantilever fashion and since the feed shaftfor the base extends substantially at the center thereof it is difficultto locate the feed shaft in a plane perpendicular to the axis of thegrinding wheel and passing substantially the center of the width of thegrinding wheel. For this reason, under an extremely large cuttingresistance as in the high-speed grinding operation, such large cuttingresistance applies a rotary moment to the grinding wheel base to renderdifficult smooth sliding movement of the base.

SUMMARY OF THE INVENTION It is an object of this invention to provide animproved grinding machine capable of operating at high speeds withoutdecreasing the working accuracy by the effect of vibration and weight ofthe driving motor.

According to this invention there is provided a grinding machinecomprising a stationary bed, a motor-driven grinding wheel, a base forsupporting the grinding wheel and secured to the bed, a table movablymounted on the bed, a headstock mounted on the table to support aworkpiece, and a feed shaft for feeding the table toward the grindingwheel to grind the workpiece by the grinding wheel, the feed shaft beinglocated in a plane perpendicular to the axis of the grinding wheel andpassing through substantially the center of the width of the grindingwheel.

The base of the grinding wheel is pivotally mounted on the bed and thebed is formed with one or more arcuate groove to receive T-bolts securedto the base. This permit swinging motion of the bed to a positionconvenient for exchanging the grinding wheel.

BRIEF DESCRIPTION OF THE DRAWINGS The invention can be more fullyunderstood from the following detailed description when taken inconjunction with the accompanying drawings in which:

FIG. 11 is a plan view of a grinding machine embodying this invention;

FIG. 2 is a sectional view taken along a line lI-II in FIG. 1;

FIG. 3 is a partial sectional view taken along a line IIl--III in FIG.ll;

FIG. 4 is a partial side view as viewed in the direction of an arrow IVin FIG. 1;

FIG. 5 is a sectional view taken along a line V-V in FIG. 2; FIG. 6 is asectional view taken along a line VI -VI in FIG.

FIG. 7 is a sectional view taken along a line VlI--Vll in FIG.

FIG. 8 is a sectional view taken along a line VIIIVIII in FIG. 7;

FIG. 9 is a sectional view taken along a line lX-IX in FIG.

FIG. 10 is an enlarged sectional view of the portions encircled by acircle X in FIG. I and;

FIG. 11 is a sectional view taken along a line XI-Xl in FIG. III.

2 DESCRIPTION OF THE PREFERRED EMBODIMENT The embodiment of theinvention shown in FIG. I and 2 comprises a. stationary bed I having astationary base 2 thereon. A grinding wheelbase 3 is pivotally mountedon the stationary base 2 about a pivot shaft 1. A grinding wheel spindle6 supporting a grinding wheel 5 at one end thereof is rotatablyjournaled by the grinding wheelbase 3 and on the outer end of spindle 6is keyed a pulley 7. A motor base 9 supporting an electric motor 8 fordriving the grinding wheel 5' is mounted on base 3 to be adjustable bymeans of an adjusting screw lit]. The pulley '7 and a pulley l2 keyed toa motor shaft 11 are operatively connected by transmission belts I3.Thus, the motor 8 drives the grinding wheel 5 at a high speed throughpulleys 7 and I2 and the belt 113. As shown in FIG. I and FIG. 3 acontinuous chain M is mounted on the rear side of the base 3 to engage asprocket wheel 15 keyed to one end of a shaft 116 which is rotatablysupported by bearings 115, lid in a bracket 117 secured to bed I. Shaft16 is provided with an integral pinion I9 meshing racked rod 21connected to the piston rod (not shown) of a piston cylinder assembly20. As shown in FIG. 41, a stop 22 is secured to the rear surface ofbase 3 to engage a bolt 24 threaded in a stop member 23 secured to thebase 2. Upon operation of the piston cylinder assembly 20 the grindingwheel supporting base 3 is pivoted about pivot shaft 4 to a position notinterfering with a head stock 55, a tailstock 57, and others during thegrinding wheel exchanging operation. Moreover, it may be realized tooperate the desired tapered grinding operation by means of pivotalmovement of grinding wheelbase 3. This pivotal movement in one directionis limited by the stroke of the piston cylinder assembly 20 while thatin the opposite direction is limited by the engagement of bolt 24! andstop 22. Further, an adjusting bolt 25 is threaded through stop 22 toengage a measuring member 27 of a dial gauge 26 secured to stop member23 thereby providing fine adjustments of the pivoted position of thebase 3. Arcuate T-shaped grooves 25, 28, 2d are formed on the surface ofstationary base 2 about pivot shaft 4, as shown in FIG. l, to receiveheads of T-bolts 39 provided with nuts 29 and extending through base 3as best shown in FIG. 3. Consequently, when nuts 29 are loosened base 3can be rotated about pivot shaft 4 whereas when nuts 29 are tightenedbase 3 is fixedly secured to stationary base 2.

A table 35 (as shown in FIG. ]l) is movably supported on the bed I bymeans of four supporting rollers 311, 32, 33 and 3d. A headstock 56rotatably supporting a work spindle 55, and a tailstock 57 are mountedon table 35. Headstock 56 supports an electric motor 58 with a reductiongearing, the rotary mo tion of motor 58 being transmitted to main shaft55 through X transmission belts 59. A workpiece MI is mounted on thefront end of the work spindle 55 by means of a suitable chuck.

Beneath the central portion of table 35 are secured two supportingplates 39 which are supported by rollers 31 and 32. As shown in FIGS. 2and 5 these rollers are keyed to shaft 39 rotatably journaled inbearings 37 in supporting brackets 36 secured to bed ll. Each supportingbracket 36 securely holds a vertical shaft 40 and rotatably supports avertical shaft all and guide rollers 42 and 43 are rotatably mounted onthe upper ends of shafts 40 and M as shown in FIG. 5. Each of thesupporting plates 39 described above is interposed between guide rollers42 and 453 to guide table 35 in the longitudinal direction of thesupporting plates 39. Guide roller 43 is eccentrically mounted on shaft411 by an amount L so that by rotating shaft d]! it is possible toadjust the clamping force applied to guide plate 39 by guide rollers 42and III. More particularly, a worm wheel 46 is keyed to one end of shaft41 to mesh a worm 45 formed on a shaft M which is rotatably supported bya bracket 191 secured to the bracket 36 as best shown in FIG. 6. Theother end of worm shaft M is connected to an operating shaft 48 througha universal joint 47, the opposite end of the operating shaft beingoperable from outside of bed I as shown in FIG. 1. Thus, by rotatingoperating shaft 458 it is possible to adjust to any desired value of theclamping force for the supporting plate exerted by guide rollers 42 andI3.

As shown in FIGS. 7 and 8 a supporting plate 98 is secured to the lowerside of the table 35 on one side thereof and the supporting plate 98 issupported by supporting rollers 33 and 34 described above. Each of thesupporting rollers is keyed to a shaft 51 rotatably supported by asliding member 49 through bearings 50. The sliding member 49 is slidablymounted on sliding members 52 secured to bed 1; the guide surfaces 53 ofsliding members 52 being longitudinally slightly inclined. Each of thesliding members 49 threadedly receives the inner end of an operatingshaft 54 having an outer end operable from outside. Thus, by rotatingthese operating shafts slidable members 49 are reciprocated alonginclined guide surfaces 53 of sliding members 52 whereby to adjustsupporting rollers in the vertical direction to correct the inclinationof the table 35.

As shown in FIGS. 2 and 9, a vibration-absorbing plate 61 having aletter L shaped cross section is secured on the upper surface of bed 1along the sliding direction of table 35. The vertical legged portion ofthis vibration-absorbing plate 61 is clamped between a pair of arms 62and 63 via vibrationabsorbing members 64 made of Teflon (registeredtrademark), for example, thereby to absorb vibrations of table 35 duringits sliding movement.

As shown in FIG. 9, arm 62 has a horizontal cylindrical portion 62aaxially slidably received in a bore in a bracket 65 secured to table 35,while arm 63 is provided with a plunger 66 slidably received in saidcylindrical portion 62a. A threaded rod 68 is received in a lid 67 ofthe cylindrical portion 62a of arm 62 such that it can rotate freely butcan not move axially. The inner end of rod 68 is threaded in plunger 66and the outer end carries a worm wheel 69 keyed thereto and meshing aworm 71a on shaft 70. Thus rotation of shaft 70 moves arms 62 and 63towards and away each other to adjust the clamping force exerted uponvibration absorbing plate 61 thus effectively absorbing vibrations ofthe table 35 created at the time of its sliding movement.

To the rear side of bed 1, is provided a table feed mechanism (as shownin FIG. 2) which reciprocate table 35. More particularly, as shown inFIGS. and 11, a gearbox 71 is secured to the rear side of bed 1 and anelectrohydraulic pulse motor 72 is secured to the outside of gearbox 71.A gear 75 rotatably received in bearings 74 secured to gearbox 71 iskeyed to the output shaft 73 of electrohydraulic pulse motor 72. Gear 75meshes a gear 80 keyed to a feed shaft 78. Feed shaft 78 is rotatablymounted in bearings 77 in gearbox 71 in a plane perpendicular to theaxis of the grinding wheel 5 and passing through substantially thecenter of the width of the grinding wheel. With this arrangement, thegrinding resistance acts directly upon shaft 78 and does not apply anyrotary mo ment to table 35. Further, feed shaft 78 is located on theline passing through the center of gravity of table 35. Gear 80comprises two spur gears 81 and 82 which are impacted with a relativetorque by suitable means (not shown) to eliminate the backlash of thegear. Another gearbox 83 is secured to the rear surface of table 35 anda nut housing member 79 is rotatably received in gearbox 83 throughbearings 85. A feed nut 84 is solidly secured in nut housing member 79.Feed shaft 78 mates with feed nut 84 through a train of balls (notshown), said feed shaft 78, balls and feed nut 84 cooperate toconstitute a ball screw device. As shown in FIG. 11 an electrohydraulicpulse motor 86 is secured to gearbox 83 and a worm 88 is keyed to anoutput shaft 87 of the electrohydraulic pulse motor 86. The worm 88meshes a worm wheel 90 keyed to shaft 87 which is rotatably joumaled bygearings 91 in a sleeve 97 inserted in gearbox 83. A worm 92 formed onworm shaft 89 meshes a worm wheel 93 which is keyed to a supportingsleeve 94 and is further held stationary by nuts 95. One end of sleeve94 is rotatably mounted in bearings 96 in a sleeve 100 secured togearbox 83 while the other end is connected with nut housing member 79through coupling teeth 97. As shown in FIG. 10, feed shaft 78 freelyextends through sleeve 94. As the electrohydraulic pulse motor 72 isenergized by an electric pulse the rotation of pulse motor 72 istransmitted to feed shaft 78 through gears 75 and 80. At this time,

since feed nut 84 is prevented from being rotated by worm 92 and wormwheel 93 table 35 will be fed forwardly at a high speed by the ballscrew device comprising feed shaft 78, balls (not shown) and feed nut84. After table 35 has been quickly advanced a predeten'nined distanceelectrohydraulic pulse motor 72 is deenergized to stop rotation of feedshaft 78. When an electric pulse is supplied to electrohydraulic pulsemotor 86 the rotation thereof will be transmitted to feed nut 84 viagears 88, 90, worm shaft 89, worm 92, worm wheel 93 and sleeve 94 toapply the required grinding feed to table 35 through above-mentionedball screw device to grind at high speed the workpiece 60 by grindingwheel 5.

As above described, according to this invention the base of a grindingwheel upon which a grinding wheel driving motor is mounted is fixedlysecured on a massive bed and a table is supported on the bed such thatthe table is movable toward the axis of the grinding wheel thereby toadvance the table for grinding operation. Accordingly, it is notnecessary to feed the grinding wheel base supporting the massive andvibrating driving motor. In addition, different from the connectionaldesign of feeding the grinding wheel base there is no fear of decreasingthe working accuracy caused by the adverse effect of the weight andvibration of the grinding wheel driving motor upon fine feeding of thegrinding wheel base and upon the accuracy of the stopping thereof.Instead of sliding the grinding wheel base as in the conventionaldesign, according to this invention the table is constructed to bemovable and the feed shaft for feeding the table is located in a planeperpendicular to the axis of the grinding wheel and passing through thecenter of the width of the grinding wheel so that even when a highgrinding resistance produced at the time of high-speed working isapplied on the table no rotary moment is applied to the table thusensuring smooth sliding movement thereof.

While in the above-described embodiment as a table feed device was useda combination of a feed screw device and an electrohydraulic pulse motorit should be understood that this invention is by no means limited tothis particular table feed device but any well known automatic or manualtable feed device can also be used.

We claim:

1. A grinding machine comprising a stationary bed, a motordrivengrinding wheel, a base for supporting mid grinding wheel and secured tosaid bed, a table movably mounted on said bed, a headstock mounted onsaid table to support a workpiece, and a feed shaft for feeding saidtable toward said grinding wheel to grind said workpiece by saidgrinding wheel, said feed shaft being located in a plane perpendicularto the axis of said grinding wheel and passing through substantially thecenter of the width of said grinding wheel.

2. A grinding machine comprising a stationary bed, a grinding wheel basesecured to said bed and rotatably supports a grinding wheel, drivingmeans for rotating said grinding wheel, a table movably supported onsaid bed, a headstock mounted on said table to rotatably support a workspindle, drive means for rotating said work spindle, a feed shaft forsaid table located in a plane perpendicular to the axis of said grindingwheel and passing through substantially the middle of the width of saidgrinding wheel, screw means to operatively couple said feed shaft tosaid table, feed means to drive said feed shaft, and guide means toguide said table in the axial direction of said feed shaft whereby tofeed said table to grind a workpiece supported by said headstock.

3. The grinding machine according to claim 2 wherein said guide meanscomprises supporting rollers rotatably mounted on said bed in a planeperpendicular to the axis of said feed shaft and in parallel planes onboth sides of said planes, and a supporting member on said table toengage at least the outer periphery of said supporting roller.

4. The grinding machine according to claim I which further comprisesmeans for absorbing vibrations of said table, said means being locatedin planes parallel to the axis of said feed shaft.

I. The grinding machine according to claim 5, wherein said means forrotating said grinding wheelbase comprises a piston cylinder assemblysecured on said bed, a sprocket wheel connected to said piston cylinderassembly through gear mechanism, and a continuous chain mounted on saidgrinding wheelbase and engaged with said sprocket wheel, whereby saidgrinding wheelbase is pivoted about said pivot shaft by means of saidpiston cylinder assembly.

1. A grinding machine comprising a stationary bed, a motordrivengrinding wheel, a base for supporting said grinding wheel and secured tosaid bed, a table movably mounted on said bed, a headstock mounted onsaid table to support a workpiece, and a feed shaft for feeding saidtable toward said grinding wheel to grind said workpiece by saidgrinding wheel, said feed shaft being located in a plane perpendicularto the axis of said grinding wheel and passing through substantially thecenter of the width of said grinding wheel.
 2. A grinding machinecomprising a stationary bed, a grinding wheel base secured to said bedand rotatably supports a grinding wheel, driving means for rotating saidgrinding wheel, a table movably supported on said bed, a headstockmounted on said table to rotatably support a work spindle, drive meansfor rotating said work spindle, a feed shaft for said table located in aplane perpendicular to the axis of said grinding wheel and passingthrough substantially the middle of the width of said grinding wheel,screw means to operatively couple said feed shaft to said table, feedmeans to drive said feed shaft, and guide means to guide said table inthe axial direction of said feed shaft whereby to feed said table togrind a workpiece supported by said headstock.
 3. The grinding machineaccording to claim 2 wherein said guide means comprises supportingrollers rotatably mounted on said bed in a plane perpendicular to theaxis of said feed shaft and in parallel planes on both sides of saidplanes, and a supporting member on said table to engage at least theouter periphery of said supporting roller.
 4. The grinding machineaccording to claim 1 which further comprises means for absorbingvibrations of said table, said means being located in planes parallel tothe axis of said feed shaft.
 5. The grinding machine according to claim1 wherein said grinding wheel base is pivotally mounted on saidstationary base about a pivot shaft and wherein there are provided anarcuate guide groove for guiding the pivotal movement of said grindingwheelbase and means to rotate said base about said pivot shaft.
 6. Thegrinding machine according to claim 2, wherein said feed means fordriving said shaft comprises electrohydraulic pulse motors mounted onsaid bed and said table for rapid feed motion and grinding feed motionrespectively.
 7. The grinding machine according to claim 5, wherein saidmeans for rotating said grinding wheelbase comprises a piston cylinderassembly secured on said bed, a sprocket wheel connected to said pistoncylinder assembly through gear mechanism, and a continuous chain mountedon said grinding wheelbase and engaged with said sprocket wheel, wherebysaid grinding wheelbase is pivoted about said pivot shaft by means ofsaid piston cylinder assembly.